// Returns a new list of elements matching the given CSS selector selectorQuery. 
// If there are no matching elements, an empty list is returned.
// Standard CSS2 selector syntax is used for the query.

QWebElement QWebFrame::findFirstElement ( const QString & selectorQuery ) const

QByteArray arr = networkReply->readAll();
QTextStream stream(arr);
while (!stream.atEnd)
{
  QString str(stream.realLine());
  QRegExp exp("your_pattern");
  int index = -1;
  while ((index = str.indexOf(exp, index + 1) != -1)
  {
    int end = str.indexOf(".mp3", index);
    QString url = str.mid(index, end - index + 4);
    ...
  }
}

// main.cpp:

#include <QDebug>
#include <QApplication>
#include <QWebView>
#include <QWebFrame>
#include <QWebElement>
#include <QRegExp>
#include <QMainWindow>

class MainWindow : public QMainWindow {
public:
    MainWindow(QWidget *parent = 0)
    : QMainWindow(parent)
    {
        QWebView *view = new QWebView(this);
        setCentralWidget(view);

        view->setHtml(
          "<div class=\"audioRow fl_l\" id=\"audio84522151_33\" onmouseover=\"addClass(this, 'over')\" onmouseout=\"removeClass(this, 'over')\">"
          "<div class=\"repeat_wrap\"><div onmouseover=\"showTooltip(this, window.lang_repeat_audio)\" "
          "onmouseout=\"hideTooltip()\" id=\"repeat84522151_33\" class=\"fl_r repeat\" onclick=\"AudioObject.toggleRepeat()\"></div></div>"
          "<div class=\"fl_l\">"
          "<a name=\"84522151_33\"></a>"
          "<table cellpadding=\"0\" cellspacing=\"0\"><tbody>"
          "<tr><td class=\"play_btn\">"
          "<img class=\"playimg\" onclick=\"return operate('84522151_33','http://cs5024.vkontakte.ru/u46191745/audio/0df7aabdd412.mp3',239);\" "
          "id=\"imgbutton84522151_33\" nosorthandle=\"true\" src=\"images/play.gif\"/>"
          "</td>"

          "<td class=\"play_title\"><div class=\"audioTitle\">"
          "<b id=\"performer84522151_33\"><a href='gsearch.php?section=audio&c[q]=Jean Michel Jarre'>Jean Michel Jarre</a></b><span> - </span>"
          "<span id=\"title84522151_33\">Magnetic Fields Part 2</span> </div>"
          "<div class=\"duration\">3:59</div>"
          "</td>"
          "</tr>"
          "</tbody></table>"
        );


        QWebFrame *frame = view->page()->mainFrame();
        QString attr = frame->findFirstElement("img.playimg").attribute("onclick", "<onclick>");

        qDebug() << attr; // "return operate('84522151_33','http://cs5024.vkontakte.ru/u46191745/audio/0df7aabdd412.mp3',239);"
        qDebug() << frame->findFirstElement("div.audioTitle").toPlainText(); // "Jean Michel Jarre - Magnetic Fields Part 2"

        QRegExp rx("(http.*\\.mp3)");
        if (rx.indexIn(attr, 0) != -1) {
            qDebug() << rx.cap(1); // "http://cs5024.vkontakte.ru/u46191745/audio/0df7aabdd412.mp3"
        }
    }

    ~MainWindow() {}
};


int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();

    return a.exec();
}